Bismuth Orthosilicate, 2Bi₂O₃.3SiO₂

Bismuth Orthosilicate, 2Bi₂O₃.3SiO₂, is found in nature in the minerals eulytite and agricolite, the former crystallising in the tetrahedral system and the latter in the monoclinic. Thermal and microscopical examination of mixtures of bismuth trioxide and silica revealed the existence of several silicates which have since been synthesised. These are indicated below.

Formula.	M.pt. (° C.).	Density (20° C.).
Bi2O3.8SiO2	992	6.623
Bi2O3.3SiO2	847	8.107
Bi2O3.2SiO2	873	8.657
2Bi2O3.3SiO2	736 to 877	8.984
Bi2O3.SiO2	772 to 890	8.924
3Bi2O3.2SiO2	791	8.388
2Bi2O3.SiO2	803 to 843	9.138
3Bi2O3.SiO2	822	8.897
10Bi2O3.SiO2	832	9.136